const fn3: FindFristFn = (arr) => {
  return arr[0];
};

const arr = ['123', 123];
type ParamType = typeof arr;

type FindFristFn = <T>(aa: T[]) => T; // typeof  ['123', 123]
const result66 = fn3(['123', 123]); //(stirng | number)[]
const str = fn3(['123', '456']); // string[]
